1249ac17eSChris Zankel/* 2249ac17eSChris Zankel * arch/xtensa/lib/strncpy_user.S 3249ac17eSChris Zankel * 4249ac17eSChris Zankel * This file is subject to the terms and conditions of the GNU General 5249ac17eSChris Zankel * Public License. See the file "COPYING" in the main directory of 6249ac17eSChris Zankel * this archive for more details. 7249ac17eSChris Zankel * 8249ac17eSChris Zankel * Returns: -EFAULT if exception before terminator, N if the entire 9249ac17eSChris Zankel * buffer filled, else strlen. 10249ac17eSChris Zankel * 11249ac17eSChris Zankel * Copyright (C) 2002 Tensilica Inc. 12249ac17eSChris Zankel */ 13249ac17eSChris Zankel 14249ac17eSChris Zankel#include <linux/errno.h> 150013acebSMax Filippov#include <variant/core.h> 160013acebSMax Filippov#include <asm/asmmacro.h> 17249ac17eSChris Zankel 18249ac17eSChris Zankel/* 19249ac17eSChris Zankel * char *__strncpy_user(char *dst, const char *src, size_t len) 20249ac17eSChris Zankel */ 21a0bb46baSChris Zankel 22a0bb46baSChris Zankel#ifdef __XTENSA_EB__ 23a0bb46baSChris Zankel# define MASK0 0xff000000 24a0bb46baSChris Zankel# define MASK1 0x00ff0000 25a0bb46baSChris Zankel# define MASK2 0x0000ff00 26a0bb46baSChris Zankel# define MASK3 0x000000ff 27a0bb46baSChris Zankel#else 28a0bb46baSChris Zankel# define MASK0 0x000000ff 29a0bb46baSChris Zankel# define MASK1 0x0000ff00 30a0bb46baSChris Zankel# define MASK2 0x00ff0000 31a0bb46baSChris Zankel# define MASK3 0xff000000 32a0bb46baSChris Zankel#endif 33249ac17eSChris Zankel 34249ac17eSChris Zankel# Register use 35249ac17eSChris Zankel# a0/ return address 36249ac17eSChris Zankel# a1/ stack pointer 37249ac17eSChris Zankel# a2/ return value 38249ac17eSChris Zankel# a3/ src 39249ac17eSChris Zankel# a4/ len 40249ac17eSChris Zankel# a5/ mask0 41249ac17eSChris Zankel# a6/ mask1 42249ac17eSChris Zankel# a7/ mask2 43249ac17eSChris Zankel# a8/ mask3 44249ac17eSChris Zankel# a9/ tmp 45249ac17eSChris Zankel# a10/ tmp 46249ac17eSChris Zankel# a11/ dst 47249ac17eSChris Zankel# a12/ tmp 48249ac17eSChris Zankel 49a0bb46baSChris Zankel.text 50249ac17eSChris Zankel.align 4 51249ac17eSChris Zankel.global __strncpy_user 52249ac17eSChris Zankel.type __strncpy_user,@function 53249ac17eSChris Zankel__strncpy_user: 54249ac17eSChris Zankel entry sp, 16 # minimal stack frame 55249ac17eSChris Zankel # a2/ dst, a3/ src, a4/ len 56249ac17eSChris Zankel mov a11, a2 # leave dst in return value register 57249ac17eSChris Zankel beqz a4, .Lret # if len is zero 58a0bb46baSChris Zankel movi a5, MASK0 # mask for byte 0 59a0bb46baSChris Zankel movi a6, MASK1 # mask for byte 1 60a0bb46baSChris Zankel movi a7, MASK2 # mask for byte 2 61a0bb46baSChris Zankel movi a8, MASK3 # mask for byte 3 62249ac17eSChris Zankel bbsi.l a3, 0, .Lsrc1mod2 # if only 8-bit aligned 63249ac17eSChris Zankel bbsi.l a3, 1, .Lsrc2mod4 # if only 16-bit aligned 64249ac17eSChris Zankel.Lsrcaligned: # return here when src is word-aligned 65249ac17eSChris Zankel srli a12, a4, 2 # number of loop iterations with 4B per loop 66249ac17eSChris Zankel movi a9, 3 67249ac17eSChris Zankel bnone a11, a9, .Laligned 68249ac17eSChris Zankel j .Ldstunaligned 69249ac17eSChris Zankel 70249ac17eSChris Zankel.Lsrc1mod2: # src address is odd 710013acebSMax FilippovEX(11f) l8ui a9, a3, 0 # get byte 0 72249ac17eSChris Zankel addi a3, a3, 1 # advance src pointer 730013acebSMax FilippovEX(10f) s8i a9, a11, 0 # store byte 0 74249ac17eSChris Zankel beqz a9, .Lret # if byte 0 is zero 75249ac17eSChris Zankel addi a11, a11, 1 # advance dst pointer 76249ac17eSChris Zankel addi a4, a4, -1 # decrement len 77249ac17eSChris Zankel beqz a4, .Lret # if len is zero 78249ac17eSChris Zankel bbci.l a3, 1, .Lsrcaligned # if src is now word-aligned 79249ac17eSChris Zankel 80249ac17eSChris Zankel.Lsrc2mod4: # src address is 2 mod 4 810013acebSMax FilippovEX(11f) l8ui a9, a3, 0 # get byte 0 82249ac17eSChris Zankel /* 1-cycle interlock */ 830013acebSMax FilippovEX(10f) s8i a9, a11, 0 # store byte 0 84249ac17eSChris Zankel beqz a9, .Lret # if byte 0 is zero 85249ac17eSChris Zankel addi a11, a11, 1 # advance dst pointer 86249ac17eSChris Zankel addi a4, a4, -1 # decrement len 87249ac17eSChris Zankel beqz a4, .Lret # if len is zero 880013acebSMax FilippovEX(11f) l8ui a9, a3, 1 # get byte 0 89249ac17eSChris Zankel addi a3, a3, 2 # advance src pointer 900013acebSMax FilippovEX(10f) s8i a9, a11, 0 # store byte 0 91249ac17eSChris Zankel beqz a9, .Lret # if byte 0 is zero 92249ac17eSChris Zankel addi a11, a11, 1 # advance dst pointer 93249ac17eSChris Zankel addi a4, a4, -1 # decrement len 94249ac17eSChris Zankel bnez a4, .Lsrcaligned # if len is nonzero 95249ac17eSChris Zankel.Lret: 96249ac17eSChris Zankel sub a2, a11, a2 # compute strlen 97249ac17eSChris Zankel retw 98249ac17eSChris Zankel 99249ac17eSChris Zankel/* 100249ac17eSChris Zankel * dst is word-aligned, src is word-aligned 101249ac17eSChris Zankel */ 102249ac17eSChris Zankel .align 4 # 1 mod 4 alignment for LOOPNEZ 103249ac17eSChris Zankel .byte 0 # (0 mod 4 alignment for LBEG) 104249ac17eSChris Zankel.Laligned: 105249ac17eSChris Zankel#if XCHAL_HAVE_LOOPS 106249ac17eSChris Zankel loopnez a12, .Loop1done 107249ac17eSChris Zankel#else 108249ac17eSChris Zankel beqz a12, .Loop1done 109249ac17eSChris Zankel slli a12, a12, 2 110249ac17eSChris Zankel add a12, a12, a11 # a12 = end of last 4B chunck 111249ac17eSChris Zankel#endif 112249ac17eSChris Zankel.Loop1: 1130013acebSMax FilippovEX(11f) l32i a9, a3, 0 # get word from src 114249ac17eSChris Zankel addi a3, a3, 4 # advance src pointer 115249ac17eSChris Zankel bnone a9, a5, .Lz0 # if byte 0 is zero 116249ac17eSChris Zankel bnone a9, a6, .Lz1 # if byte 1 is zero 117249ac17eSChris Zankel bnone a9, a7, .Lz2 # if byte 2 is zero 1180013acebSMax FilippovEX(10f) s32i a9, a11, 0 # store word to dst 119249ac17eSChris Zankel bnone a9, a8, .Lz3 # if byte 3 is zero 120249ac17eSChris Zankel addi a11, a11, 4 # advance dst pointer 121249ac17eSChris Zankel#if !XCHAL_HAVE_LOOPS 122249ac17eSChris Zankel blt a11, a12, .Loop1 123249ac17eSChris Zankel#endif 124249ac17eSChris Zankel 125249ac17eSChris Zankel.Loop1done: 126249ac17eSChris Zankel bbci.l a4, 1, .L100 127249ac17eSChris Zankel # copy 2 bytes 1280013acebSMax FilippovEX(11f) l16ui a9, a3, 0 129249ac17eSChris Zankel addi a3, a3, 2 # advance src pointer 130249ac17eSChris Zankel#ifdef __XTENSA_EB__ 131249ac17eSChris Zankel bnone a9, a7, .Lz0 # if byte 2 is zero 132249ac17eSChris Zankel bnone a9, a8, .Lz1 # if byte 3 is zero 133249ac17eSChris Zankel#else 134249ac17eSChris Zankel bnone a9, a5, .Lz0 # if byte 0 is zero 135249ac17eSChris Zankel bnone a9, a6, .Lz1 # if byte 1 is zero 136249ac17eSChris Zankel#endif 1370013acebSMax FilippovEX(10f) s16i a9, a11, 0 138249ac17eSChris Zankel addi a11, a11, 2 # advance dst pointer 139249ac17eSChris Zankel.L100: 140249ac17eSChris Zankel bbci.l a4, 0, .Lret 1410013acebSMax FilippovEX(11f) l8ui a9, a3, 0 142249ac17eSChris Zankel /* slot */ 1430013acebSMax FilippovEX(10f) s8i a9, a11, 0 144249ac17eSChris Zankel beqz a9, .Lret # if byte is zero 145249ac17eSChris Zankel addi a11, a11, 1-3 # advance dst ptr 1, but also cancel 146249ac17eSChris Zankel # the effect of adding 3 in .Lz3 code 147249ac17eSChris Zankel /* fall thru to .Lz3 and "retw" */ 148249ac17eSChris Zankel 149249ac17eSChris Zankel.Lz3: # byte 3 is zero 150249ac17eSChris Zankel addi a11, a11, 3 # advance dst pointer 151249ac17eSChris Zankel sub a2, a11, a2 # compute strlen 152249ac17eSChris Zankel retw 153249ac17eSChris Zankel.Lz0: # byte 0 is zero 154249ac17eSChris Zankel#ifdef __XTENSA_EB__ 155249ac17eSChris Zankel movi a9, 0 156249ac17eSChris Zankel#endif /* __XTENSA_EB__ */ 1570013acebSMax FilippovEX(10f) s8i a9, a11, 0 158249ac17eSChris Zankel sub a2, a11, a2 # compute strlen 159249ac17eSChris Zankel retw 160249ac17eSChris Zankel.Lz1: # byte 1 is zero 161249ac17eSChris Zankel#ifdef __XTENSA_EB__ 162249ac17eSChris Zankel extui a9, a9, 16, 16 163249ac17eSChris Zankel#endif /* __XTENSA_EB__ */ 1640013acebSMax FilippovEX(10f) s16i a9, a11, 0 165249ac17eSChris Zankel addi a11, a11, 1 # advance dst pointer 166249ac17eSChris Zankel sub a2, a11, a2 # compute strlen 167249ac17eSChris Zankel retw 168249ac17eSChris Zankel.Lz2: # byte 2 is zero 169249ac17eSChris Zankel#ifdef __XTENSA_EB__ 170249ac17eSChris Zankel extui a9, a9, 16, 16 171249ac17eSChris Zankel#endif /* __XTENSA_EB__ */ 1720013acebSMax FilippovEX(10f) s16i a9, a11, 0 173249ac17eSChris Zankel movi a9, 0 1740013acebSMax FilippovEX(10f) s8i a9, a11, 2 175249ac17eSChris Zankel addi a11, a11, 2 # advance dst pointer 176249ac17eSChris Zankel sub a2, a11, a2 # compute strlen 177249ac17eSChris Zankel retw 178249ac17eSChris Zankel 179249ac17eSChris Zankel .align 4 # 1 mod 4 alignment for LOOPNEZ 180249ac17eSChris Zankel .byte 0 # (0 mod 4 alignment for LBEG) 181249ac17eSChris Zankel.Ldstunaligned: 182249ac17eSChris Zankel/* 183249ac17eSChris Zankel * for now just use byte copy loop 184249ac17eSChris Zankel */ 185249ac17eSChris Zankel#if XCHAL_HAVE_LOOPS 186249ac17eSChris Zankel loopnez a4, .Lunalignedend 187249ac17eSChris Zankel#else 188249ac17eSChris Zankel beqz a4, .Lunalignedend 189249ac17eSChris Zankel add a12, a11, a4 # a12 = ending address 190249ac17eSChris Zankel#endif /* XCHAL_HAVE_LOOPS */ 191249ac17eSChris Zankel.Lnextbyte: 1920013acebSMax FilippovEX(11f) l8ui a9, a3, 0 193249ac17eSChris Zankel addi a3, a3, 1 1940013acebSMax FilippovEX(10f) s8i a9, a11, 0 195249ac17eSChris Zankel beqz a9, .Lunalignedend 196249ac17eSChris Zankel addi a11, a11, 1 197249ac17eSChris Zankel#if !XCHAL_HAVE_LOOPS 198249ac17eSChris Zankel blt a11, a12, .Lnextbyte 199249ac17eSChris Zankel#endif 200249ac17eSChris Zankel 201249ac17eSChris Zankel.Lunalignedend: 202249ac17eSChris Zankel sub a2, a11, a2 # compute strlen 203249ac17eSChris Zankel retw 204249ac17eSChris Zankel 205249ac17eSChris Zankel 206249ac17eSChris Zankel .section .fixup, "ax" 207249ac17eSChris Zankel .align 4 208249ac17eSChris Zankel 209249ac17eSChris Zankel /* For now, just return -EFAULT. Future implementations might 210249ac17eSChris Zankel * like to clear remaining kernel space, like the fixup 211249ac17eSChris Zankel * implementation in memset(). Thus, we differentiate between 212249ac17eSChris Zankel * load/store fixups. */ 213249ac17eSChris Zankel 2140013acebSMax Filippov10: 2150013acebSMax Filippov11: 216249ac17eSChris Zankel movi a2, -EFAULT 217249ac17eSChris Zankel retw 218